The alert functionality is an out of range indicator and can be used as an early indicator of an out of bounds conversion result. ALERT_LOW_THRESHOLD and ALERT_HIGH_THRESHOLD registers are common to all channels. When using 1 SDO line (only mode supported by the driver right now), i.e data outputs only on SDOA, SDOB (or SDOD for 4 channels variants) is used as an alert pin. The alert pin is updated at the end of the conversion (set to low if an alert occurs) and is cleared on a falling edge of CS. The ALERT register contains information about the exact alert status: channel and direction. ALERT register can be accessed using debugfs if enabled. User can set high/low thresholds and enable alert detection using the regular iio events attributes: events/in_thresh_falling_value events/in_thresh_rising_value events/thresh_either_en In most use cases, user will hardwire the alert pin to trigger a shutdown. In theory, we could generate userspace IIO events for alerts, but this is not implemented yet for several reasons [1]. This can be implemented later if a real use case actually requires it. Signed-off-by: Julien Stephan <jstephan@xxxxxxxxxxxx> [1] https://lore.kernel.org/all/4be16272-5197-4fa1-918c-c4cdfcaee02e@xxxxxxxxxxxx/ --- drivers/iio/adc/ad7380.c | 197 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 197 insertions(+) diff --git a/drivers/iio/adc/ad7380.c b/drivers/iio/adc/ad7380.c index a532de4422082df8503454d66fc49f75b52cff68..cedd45556ee38b3197f8dd7edea162c3f4ba1563 100644 --- a/drivers/iio/adc/ad7380.c +++ b/drivers/iio/adc/ad7380.c @@ -34,6 +34,7 @@ #include <linux/util_macros.h> #include <linux/iio/buffer.h> +#include <linux/iio/events.h> #include <linux/iio/iio.h> #include <linux/iio/trigger_consumer.h> #include <linux/iio/triggered_buffer.h> @@ -112,6 +113,24 @@ struct ad7380_chip_info { const struct ad7380_timing_specs *timing_specs; }; +static const struct iio_event_spec ad7380_events[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_shared_by_dir = BIT(IIO_EV_INFO_VALUE), + }, + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_FALLING, + .mask_shared_by_dir = BIT(IIO_EV_INFO_VALUE), + }, + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_EITHER, + .mask_shared_by_all = BIT(IIO_EV_INFO_ENABLE), + }, +}; + enum { AD7380_SCAN_TYPE_NORMAL, AD7380_SCAN_TYPE_RESOLUTION_BOOST, @@ -214,6 +233,8 @@ static const struct iio_scan_type ad7380_scan_type_16_u[] = { .has_ext_scan_type = 1, \ .ext_scan_type = ad7380_scan_type_##bits##_##sign, \ .num_ext_scan_type = ARRAY_SIZE(ad7380_scan_type_##bits##_##sign), \ + .event_spec = ad7380_events, \ + .num_event_specs = ARRAY_SIZE(ad7380_events), \ } #define AD7380_CHANNEL(index, bits, diff, sign) \ @@ -1157,12 +1178,188 @@ static int ad7380_get_current_scan_type(const struct iio_dev *indio_dev, : AD7380_SCAN_TYPE_NORMAL; } +static int ad7380_read_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir) +{ + struct ad7380_state *st = iio_priv(indio_dev); + int tmp, ret; + + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = regmap_read(st->regmap, AD7380_REG_ADDR_CONFIG1, &tmp); + + iio_device_release_direct_mode(indio_dev); + + if (ret) + return ret; + + return FIELD_GET(AD7380_CONFIG1_ALERTEN, tmp); +} + +static int ad7380_write_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + bool state) +{ + struct ad7380_state *st = iio_priv(indio_dev); + int ret; + + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = regmap_update_bits(st->regmap, + AD7380_REG_ADDR_CONFIG1, + AD7380_CONFIG1_ALERTEN, + FIELD_PREP(AD7380_CONFIG1_ALERTEN, state)); + + iio_device_release_direct_mode(indio_dev); + + return ret; +} + +static int ad7380_get_alert_th(struct ad7380_state *st, + enum iio_event_direction dir, + int *val) +{ + int ret, tmp; + + switch (dir) { + case IIO_EV_DIR_RISING: + ret = regmap_read(st->regmap, + AD7380_REG_ADDR_ALERT_HIGH_TH, + &tmp); + if (ret) + return ret; + + *val = FIELD_GET(AD7380_ALERT_HIGH_TH, tmp); + ret = IIO_VAL_INT; + break; + case IIO_EV_DIR_FALLING: + ret = regmap_read(st->regmap, + AD7380_REG_ADDR_ALERT_LOW_TH, + &tmp); + if (ret) + return ret; + + *val = FIELD_GET(AD7380_ALERT_LOW_TH, tmp); + ret = IIO_VAL_INT; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static int ad7380_read_event_value(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, + int *val, int *val2) +{ + struct ad7380_state *st = iio_priv(indio_dev); + int ret; + + switch (info) { + case IIO_EV_INFO_VALUE: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = ad7380_get_alert_th(st, dir, val); + + iio_device_release_direct_mode(indio_dev); + return ret; + default: + return -EINVAL; + } +} + +static int ad7380_set_alert_th(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_direction dir, + int val) +{ + struct ad7380_state *st = iio_priv(indio_dev); + const struct iio_scan_type *scan_type; + u16 th; + + /* + * According to the datasheet, + * AD7380_REG_ADDR_ALERT_HIGH_TH[11:0] are the 12 MSB of the + * 16-bits internal alert high register. LSB are set to 0xf. + * AD7380_REG_ADDR_ALERT_LOW_TH[11:0] are the 12 MSB of the + * 16 bits internal alert low register. LSB are set to 0x0. + * + * When alert is enabled the conversion from the adc is compared + * immediately to the alert high/low thresholds, before any + * oversampling. This means that the thresholds are the same for + * normal mode and oversampling mode. + */ + + /* Extract the 12 MSB of val */ + scan_type = iio_get_current_scan_type(indio_dev, chan); + if (IS_ERR(scan_type)) + return PTR_ERR(scan_type); + + th = val >> (scan_type->realbits - 12); + + switch (dir) { + case IIO_EV_DIR_RISING: + return regmap_write(st->regmap, + AD7380_REG_ADDR_ALERT_HIGH_TH, + th); + case IIO_EV_DIR_FALLING: + return regmap_write(st->regmap, + AD7380_REG_ADDR_ALERT_LOW_TH, + th); + default: + return -EINVAL; + } +} + +static int ad7380_write_event_value(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, + int val, int val2) +{ + int ret; + + switch (info) { + case IIO_EV_INFO_VALUE: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = ad7380_set_alert_th(indio_dev, chan, dir, val); + + iio_device_release_direct_mode(indio_dev); + return ret; + default: + return -EINVAL; + } +} + static const struct iio_info ad7380_info = { .read_raw = &ad7380_read_raw, .read_avail = &ad7380_read_avail, .write_raw = &ad7380_write_raw, .get_current_scan_type = &ad7380_get_current_scan_type, .debugfs_reg_access = &ad7380_debugfs_reg_access, + .read_event_config = &ad7380_read_event_config, + .write_event_config = &ad7380_write_event_config, + .read_event_value = &ad7380_read_event_value, + .write_event_value = &ad7380_write_event_value, }; static int ad7380_init(struct ad7380_state *st, bool external_ref_en) -- 2.47.1
